Stud driving tool

ABSTRACT

A handle having a cylindrical bore therethrough. A driving ram is slidable in the bore and adapted to drive a stud held in one end of the bore. An igniting ram is also slidable in the bore rearwardly of the driving ram. Means are provided for introducing a caseless charge between the driving ram and igniting ram.

United States Patent Pomeroy [4 1 Apr. 25, 1972 [54] STUD DRIVING TOOL 3,129,429 4/1964 l-lilti ..227/l [72] Inventor: Raymond visher Pomeroy, Portland, g 3,145,387 8/1964 Adolph ..227/l0 [73] Assignee: Omark Industries, Inc., Portland, Oreg. Primary Custer Attarney-Robert L. Harrington [22] Filed: July 30, 1970 21 Appl. No.: 59,519 [57] ABSTRACT A handle having a cylindrical bore therethrough. A driving ram is slidable in the bore and adapted to drive a stud held in U-Se I l 1 n a u 1 e l l I l s A s u n s I I 1 e l l [5]] 'f 1/14 rearwardly of the driving ram. Means are provided for in- [58] held of Search ..227/l0 troducing a caseless charge between the driving ram and i it ing ram. [56] References Cited 5 Claims, 7 Drawing Figures UNITED STATES PATENTS 3,112,487 12/1963 Hilti ..227/

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PATENTEDAPR 2 5 i972 3,658,229 SEEN 1 CF 2 ll "WWII INVENTOR. RAYMOND V. POMEROY ROBERT R. HARRINGTON ATTORNEY s'run DRIVING TOOL HISTORY This invention relates to a tool for explosively driving studs into concrete walls and the like.

Explosively actuated stud driving tools are required to satisfy a number of safety regulations. A system that is widely used for tools, primarily because it is able to readily satisfy the safety regulations, is referred to as Low Velocity Stud Driving System. In that system a driving ram slidably captured in the bored a tool is adapted to strike a stud positioned in the end of the bore thereby driving it out of the boreand into a work surface. An explosive charge is ignited in a chamber behind the ram to produce the driving force. The safety features achieved are first, in containing the explosive completely inside the tool; and second, by the indirect driving of the stud, i.e., the piston and not the stud receives the direct force of the explosive.

Heretofore the explosive charge was comprised of a cartridge type power load and loading the tool required that the tool be taken apart to extract the spent cartridge and to position a new cartridge. This process is cumbersome and objectionable to workers having to juggle the various parts under working conditions far less than ideal.

In the present invention the tool is loaded without taking it apart. It is adapted to use a caseless power load with igniting means that does not require the load to be fixedly positioned in a firing chamber. An igniting ram is slidably positioned in the bore behind the driving ram. With the igniting ram retracted, an opening through the handle permits the placement of a power load between the igniting ram and driving ram. The igniting ram is merely moved toward the driving ram to force the power load against the driving ram. A sharp blow on the igniting ram then ignites the power load for explosively propelling the driving ram.

The invention and its various modifications and embodiments will be more readily understood by reference to the following detailed description and drawings wherein,

FIG. 1 is a side view of a stud driving tool in accordance with-the present invention;

FIG. 2 is a cross section taken on section lines 2-2 of FIG.

FIG. 3 isan end view of the stud driving tool shown in FIG.

FIG. 4 is a view similar to FIG. 2 but illustrating the tool in operation;

FIG. 5 is an enlarged sectional view taken on lines 5-5 of FIG. 4;

FIG. 6 is a fragmentary view illustrating the stud driving'tool in a more advanced stage of operation as compared to FIG. 4; and

FIG. 7 illustrates a still further stage of the operation of the stud driving tool.

Referring to FIGS. 1 and 2 of the drawings, a stud driving tool 10 includes a base herein called a handle through which a bore 14 is provided. A driving ram 16 is slidable in the bore 14 and an igniting ram 18 is slidable in the bore rearwardly of the driving ram 16. (As used herein the exit end of the bore, i.e., through which a stud is driven, is referred to as the forward end). The igniting ram l8extends rearwardly out of the bandle 12 with an impact knob 20 fixed to the end of the igniting ram- 18 by a holding pin l9.

The handle 12 has a main barrel portion 22. A sleeve member 24 surrounds the barrel portion to define there between a chamber 26. Portals 28a and 28b in the barrel 22 connect the chamber 26.with the bore 14. Sealing rings 30-are provided betweenthe barrel portion and sleeve both. above and below the chamber 26. The'rearward end of the barrel portion has a threaded section 32. A retaining nut 34 engages the threaded section 32 of the'barrel portion-to enclose the end of the bore. The retaining nuthas an opening 36 that permits the shaft 38 of the igniting ram to slide therethrough but is smaller in diameter than the head portion 40. Thus with the retaining nut in place, the igniting ram can slide between two extreme positions but cannot be removed. Forward of the threaded section 32 in the barrel portion is provided an opening 42. Surrounding the barrel portion above the sleeve 24 but adapted to close the opening 42 is a cylindrical shield member 44. The shield member 44 has restricted rotative movement as permitted by the pin 46 fixed to the barrel portion and the slot 48 in the shield. An opening 50in the shield provides access to the opening 42 in the barrel and thus to the bore 14. By rotating the shield the opening 50 is misaligned with the opening 42 to close this access.

A spring loaded ball 52 in the retaining nut (loaded through opening 54) produces light friction on the shaft of the igniting ram to prohibit free sliding of the shaft therethrough. The head 40 of the igniting ram has a series of peripherial grooves 56 adjacent its forward end with a sealing ring 58 behind the grooves 56. The end face of the igniting ram is provided with relief areas in the form of radial grooves 60.

A nose portion 62 is fastened to the forward end of the barrel portion 22 by bolts 64. The bore 14 continues through the nose portion but at a reduced diameter. The reduced diameter of the nose portion permits the shaft 66 of the driving ram 16 to slide therethrough but not the head 68 thereof. The head of the driving ram is similar to the head of the igniting ram with peripherial grooves adjacent the end and a sealing ring 70 forward thereof. Radial grooves 72 are provided in the end face of the driving ram also similar to the igniting ram. A magnet 74 is positioned in the forward end of the nose portion of the bore for holding a stud in the bore as will be explained hereafter. A second magnet 74' functions to hold items such as clips and washers.

OPERATION FIG. 4 illustrates the tool in position to be loaded, i.e., the igniting ram 18 is fully retracted and the shield 44 is rotated to align openings 42 and 50. A nitrocellulose pellet, sometimes referred to as a caseless propellent, is inserted through the aligned openings and into the bore 14 between the driving ram and igniting ram. A stud 76 is inserted in the forward end of the bore 14. The head of the stud is adapted to nest in an inset 78 provided in the end ofthe driving ram. A washer 80 around the stud provides for alignment of the stud in the bore. It will be understood that such positioning of the stud in the end of the tool is accomplished with the tool held in various positions. The magnet 74 produces a holding force to maintain the stud in the tool during handling.

With the stud positioned in the end of the tool and the propellent in the bore between the driving ram and igniting ram, the end of the tool is placed against the solid work surface as seen in FIG. 4. The igniting ram is then pushed forward to compress or wedge the propellent 84 against the head of the driving ram to force the stud firmly against the work surface 82 asseen in FIG. 6. In this stacked position a hammer is used to strike the impact knob 20. The crushing force produced by the impact causes the propellent to ignite and thereby produce a force that drives the driving ram as seen in FIG. 7. The gases trapped between the igniting ram and driving ram are exhausted through the portals 28a into the chamber 26 and through portals 28b back intothe bore 14 above the head of the igniting ram.

The head portions 40 and 68 of the igniting ram and driving ram respectively are designed to accomodate the rapid expansionof gases. Thus the radial grooves on the end faces reduce the area of initial contact and provide recess areas for the propellent material to move into. Also the depth of the grooves provide an initial expansion chamber to reduce recoil. The pattern and depth of the grooves can be varied to suit conditions, e.g., strength and size of the power load, hardness of the work surface, surface area of end faces, etc. The shield member. when rotated to cover the opening 42 acts as a muffler to reduce and protect theuser from the hot blast of the gases from the exploding power load.

Many variations and modifications will be apparent to those skilled in the art and thus the scope of the invention is not to be limited to the example herein set forth but to the claims appended hereto.

What is claimed is:

1. A tool for driving studs into work surfaces comprising; a barrel having a bore extending therethrough, a driving ram and an igniting ram slidable in said bore, said igniting ram being rearward of said driving ram and having a head portion that is movable within said bore between a rearward retracted position and a forward driving ram engaging position, said barrel having an opening into the bore at a location forward of the head portion of the igniting ram when in its retracted position and rearward of the head portion in its driving ram engaging position, said opening adapted to receive a caseless propellant power load with the igniting ram retracted and said opening being substantially sealed from the power load with the head portion moved forward of the opening, the forward end of the bore adapted for receiving a stud, and the rearward end of the igniting ram protruding through the rearward end of the bore when the igniting ram, power load, driving ram and stud are in stacked arrangement, said protruding end adapted to receive an impact to ignite the power load by crushing it between the igniting ram and driving ram.

2. A tool for driving studs into a work surface as defined in claim 1 including limiting means limiting the forward movement of the igniting ram within the bore, and said barrel having portals located forwardly of the end of the igniting ram in its limited position for venting gasses from between the igniting ram and driving ram.

3. A tool for driving studs into work surfaces as defined in claim 1 wherein a shield is provided around the barrel over the opening, said shield being rotatable relative to the barrel and said shield having an opening which is aligned with the opening in the barrel at one rotative position of the shield.

4. A tool for driving studs into work surfaces as defined in claim 1 including frictional retaining means for resisting free sliding movement of the ignition ram through the bore.

5. A tool for driving studs into work surfaces as defined in claim 1 wherein one of the driving ram and the igniting ram has an end face for engaging the power load, said end face having a pattern of relief areas to facilitate crushing of the caseless power load and for initial expansion of gasses. 

1. A tool for driving studs into work surfaces comprising; a barrel having a bore extending therethrough, a driving ram and an igniting ram slidable in said bore, said igniting ram being rearward of said driving ram and having a head portion that is movable within said bore between a rearward retracted position and a forward driving ram engaging position, said barrel having an opening into the bore at a location forward of the head portion of the igniting ram when in its retracted position and rearward of the head portion in its driving ram engaging position, said opening adapted to receive a caseless propellant power load with the igniting ram retracted and said opening being substantially sealed from the power load with the head portion moved forward of the opening, the forward end of the bore adapted for receiving a stud, and the rearward end of the igniting ram protruding through the rearward end of the bore when the igniting ram, power load, driving ram and stud are in stacked arrangement, said protruding end adapted to receive an impact to ignite the power load by crushing it between the igniting ram and driving ram.
 2. A tool for driving studs into a work surface as defined in claim 1 including limiting means limiting the forward movement of the igniting ram within the bore, and said barrel having portals located forwardly of the end of the igniting ram in its limited position for venting gasses from between the igniting ram and driving ram.
 3. A tool for driving studs into work surfaces as defined in claim 1 wherein a shield is provided around the barrel over the opening, said shield being rotatable relative to the barrel and said shield having an opening which is aligned with the opening in the barrel at one rotative position of the shield.
 4. A tool for driving studs into work surfaces as defined in claim 1 including frictional retaining means for resisting free sliding movement of the ignition ram through the bore.
 5. A tool for driving studs into work surfaces as defined in claim 1 wherein one of the driving ram and the igniting ram has an end face for engaging the power load, said end face having a pattern of relief areas to facilitate crushing of the caseless power load and for initial expansion of gasses. 